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LED lighting confers many advantages, assuming you've selected the correct products for the application (including the temperature and humidity considerations we discussed in Part 2). Power distribution wiring is also an important concern.
The lamps themselves are solid-state and run on voltages similar to what devices in your computer run on. Depending upon the LED system, you might distribute 120V to each fixture (which has its own solid state power supply) or you might distribute solid state power (e.g., 5V). And there are variations in between. For example, you might distribute 120V to each of several ceiling-mounted power supplies; those supply solid state power to the individual loads you connect to their outputs. Or maybe you distribute another voltage (e.g., 30V) in a low voltage power scheme as an intermediary distribution scheme.
The distribution of low voltage is nothing new; it’s been covered by the NEC for some time now. What you must be concerned with when designing power distribution for LED systems is that systems and products come in a wide range of voltages.
If, for example, you are looking at Brand X and design the power distribution for it but then later change the specification to the Brand Y equivalent you may have a voltage mismatch. So it’s critical that you design your power distribution for the specific LED loads.
LED power distribution has another “gotcha” that we’ll discuss in Part 4.